/*
 * Copyright (c) 2011-2017 Pivotal Software Inc, All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.bytekit.log;

/**
 * Logger interface designed for internal usage.
 */
public interface Logger {

    /**
     * Return the name of this <code>Logger</code> instance.
     * 
     * @return name of this logger instance
     */
    String getName();

    /**
     * Is the logger instance enabled for the TRACE level?
     *
     * @return True if this Logger is enabled for the TRACE level, false otherwise.
     */
    boolean isTraceEnabled();

    /**
     * Log a message at the TRACE level.
     *
     * @param msg the message string to be logged
     */
    void trace(String msg);

    /**
     * Log a message at the TRACE level according to the specified format and
     * arguments.
     * <p/>
     * <p>
     * This form avoids superfluous string concatenation when the logger is disabled
     * for the TRACE level. However, this variant incurs the hidden (and relatively
     * small) cost of creating an <code>Object[]</code> before invoking the method,
     * even if this logger is disabled for TRACE.
     * </p>
     *
     * @param format    the format string
     * @param arguments a list of 3 or more arguments
     */
    void trace(String format, Object... arguments);

    /**
     * Log an exception (throwable) at the TRACE level with an accompanying message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    void trace(String msg, Throwable t);

    /**
     * Is the logger instance enabled for the DEBUG level?
     *
     * @return True if this Logger is enabled for the DEBUG level, false otherwise.
     */
    boolean isDebugEnabled();

    /**
     * Log a message at the DEBUG level.
     *
     * @param msg the message string to be logged
     */
    void debug(String msg);

    /**
     * Log a message at the DEBUG level according to the specified format and
     * arguments.
     * <p/>
     * <p>
     * This form avoids superfluous string concatenation when the logger is disabled
     * for the DEBUG level. However, this variant incurs the hidden (and relatively
     * small) cost of creating an <code>Object[]</code> before invoking the method,
     * even if this logger is disabled for DEBUG.
     * </p>
     *
     * @param format    the format string
     * @param arguments a list of 3 or more arguments
     */
    void debug(String format, Object... arguments);

    /**
     * Log an exception (throwable) at the DEBUG level with an accompanying message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    void debug(String msg, Throwable t);

    /**
     * Is the logger instance enabled for the INFO level?
     *
     * @return True if this Logger is enabled for the INFO level, false otherwise.
     */
    boolean isInfoEnabled();

    /**
     * Log a message at the INFO level.
     *
     * @param msg the message string to be logged
     */
    void info(String msg);

    /**
     * Log a message at the INFO level according to the specified format and
     * arguments.
     * <p/>
     * <p>
     * This form avoids superfluous string concatenation when the logger is disabled
     * for the INFO level. However, this variant incurs the hidden (and relatively
     * small) cost of creating an <code>Object[]</code> before invoking the method,
     * even if this logger is disabled for INFO.
     * </p>
     *
     * @param format    the format string
     * @param arguments a list of 3 or more arguments
     */
    void info(String format, Object... arguments);

    /**
     * Log an exception (throwable) at the INFO level with an accompanying message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    void info(String msg, Throwable t);

    /**
     * Is the logger instance enabled for the WARN level?
     *
     * @return True if this Logger is enabled for the WARN level, false otherwise.
     */
    boolean isWarnEnabled();

    /**
     * Log a message at the WARN level.
     *
     * @param msg the message string to be logged
     */
    void warn(String msg);

    /**
     * Log a message at the WARN level according to the specified format and
     * arguments.
     * <p/>
     * <p>
     * This form avoids superfluous string concatenation when the logger is disabled
     * for the WARN level. However, this variant incurs the hidden (and relatively
     * small) cost of creating an <code>Object[]</code> before invoking the method,
     * even if this logger is disabled for WARN.
     * </p>
     *
     * @param format    the format string
     * @param arguments a list of 3 or more arguments
     */
    void warn(String format, Object... arguments);

    /**
     * Log an exception (throwable) at the WARN level with an accompanying message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    void warn(String msg, Throwable t);

    /**
     * Is the logger instance enabled for the ERROR level?
     *
     * @return True if this Logger is enabled for the ERROR level, false otherwise.
     */
    boolean isErrorEnabled();

    /**
     * Log a message at the ERROR level.
     *
     * @param msg the message string to be logged
     */
    void error(String msg);

    /**
     * Log a message at the ERROR level according to the specified format and
     * arguments.
     * <p/>
     * <p>
     * This form avoids superfluous string concatenation when the logger is disabled
     * for the ERROR level. However, this variant incurs the hidden (and relatively
     * small) cost of creating an <code>Object[]</code> before invoking the method,
     * even if this logger is disabled for ERROR.
     * </p>
     *
     * @param format    the format string
     * @param arguments a list of 3 or more arguments
     */
    void error(String format, Object... arguments);

    /**
     * Log an exception (throwable) at the ERROR level with an accompanying message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    void error(String msg, Throwable t);

}
